The present application relates to an integrated camera and lighting device.
It is known to provide small-scale cameras, typically 32 mm in diameter, for video inspection equipment used in pipes. These can either be mounted on the end of a relatively stiff cable and pushed along the pipe, or alternatively the cameras can be mounted on self-propelled vehicles which move down the piping. Since the interior of the pipe will have no natural light it is necessary for lighting apparatus to be associated with the camera so that the interior of the pipe can be illuminated.
It is convenient to use a CMOS sensor in the camera to provide the video image. However, CMOS sensors have a disadvantage in that they are not very resistant to heat. Indeed, there is only a relatively small temperature range in which a CMOS sensor will provide a good signal.
The present invention provides an integrated camera and illumination device comprising:
illumination apparatus having a plurality of light emitting diodes arranged in a circuit which regulates current output by the circuit to an approximately constant level; and
camera apparatus having a CMOS sensor in a circuit supplied by the current regulated by the illumination apparatus.
In the above-noted construction the lighting apparatus is used to provide a constant current supply to the camera apparatus. This ensures that the CMOS sensor is maintained within a particular temperature range.
In the past switch-mode power supplies have been used or separate low-voltage feeds for the camera. The use of switch-mode power supplies increases the size of the apparatus and adds noise to the picture signals thus degrading eventual picture quality. The provision of separate supplies to the lighting apparatus and the camera apparatus considerably complicates the wiring in the apparatus and the electronics in the control unit. The present invention reduces the number of conductors required to regulate the apparatus and this means that there is no need to regulate comparatively higher voltages which would require use of additional heat-sinks and increase the size of the apparatus. The present invention provides a good quality camera apparatus in an overall package of camera and lighting apparatus which is small in size.